The invention provides a catalyst for synthesizing a nanometer molecular sieve of para-xylene and a method for preparing the same, and mainly overcomes the defects of poor stability and low selectivity on para-xylene in the prior catalyst. In the method, the nanometer molecular sieve as a mother substance, silicon, phosphorus, magnesium and mixed rare earth are modified so as to adjust acid performance and porous channel structure of the catalyst and improve the selectivity of the catalyst, and the metals with hydrogenation function such as noble metals of platinum, palladium, ruthenium, rhodium, iridium, osmium, and the like or transition metals of iron, cobalt, nickel, and the like are modified so as to inhibit the deactivation of carbon accumulation of the catalyst and greatly improve the stability of the catalyst.